Seat shell with adjustable support elements

ABSTRACT

The invention relates to a seat shell which is especially designed to be mounted on the chassis of a wheel chair or a stroller, and that comprises adjustable support elements ( 34 ) for supporting the person seated in said seat shell. The aim of the invention is to provide a seat shell with which the position of the seated person on the seat can be fixed by easily adjustable and reliably fixable support elements. To this end, the support elements ( 34 ) are disposed above the two lateral edges of the seat ( 2 ) and their distance to each other in the transverse direction of the seat ( 2 ) is adjustable.

[0001] The present invention relates to a seat shell which is provided for attachment to the chassis of a wheelchair or a stroller in particular, having a seat and a backrest, as well as adjustable support elements for supporting the person sitting in the seat shell.

[0002] A plurality of seat shells, permanently or detachably connected to a chassis of a wheelchair are known from the related art. Some have height-adjustable armrests, for example, as adjustable support elements.

[0003] Thus, for example, U.S. Pat. No. 4,039,223 describes a wheelchair in which the footrest and the backrest are fixable in different pivoting positions with respect to the seat.

[0004] European Patent Application 911 008 A2 of the Applicant shows a seat shell in which the backrest and the footrest freely pivot with respect to the seat. Furthermore, the backrest is supported by a vertical section of the wheelchair frame. The seat is held pivotably on a slide guide, which allows the seat to move forward, as well as to pivot upwardly. A tensioning device draws the seat back to its surface into its flat position where it rests on the wheelchair frame, the backrest assuming the angled position with respect to the seat. An additional tensioning device prestresses the footrest over its entire pivoting range with respect to the seat so that it is also pivoted into the angled position. The movable seat device described in this Application forms an extremely innovative and advantageous device for seating disabled patients suffering from spastic extension spasms. In such patients spastic muscle spasms cause uncontrolled extension movements. Prior to the introduction of the object of the aforementioned European Patent Application, these extension movements were absorbed by rigid wheelchairs. The device described in the aforementioned European Patent Application allows the components of the wheelchair to follow the extension movements in a controlled manner by applying an elastic restoring force. The pivot axes of the components of this seat shell are situated at the physiologically optimum pivot points, i.e., the backrest is rotatably articulated to the seat in the area of the hip joint, and the footrest is rotatably articulated to the seat in the area of the knee joint.

[0005] Finally, an additional seat shell for attachment to the chassis of a wheelchair is known from German Patent 199 30 103 C1. This seat shell has adopted the pivotable connection between the backrest and the footrest, which in this case is attached to the chassis of the wheelchair. In addition, it has thorax truss pads, i.e., support pillows for the thorax, which are attached to the back seat so they are able to pivot transversely. These support elements are adjustable by muscle force and therefore provide the person sitting in the seat only limited support. In addition, they only secure the person sitting in the seat to the back support, but not to the seat shell.

[0006] The object of the present invention is to provide a seat shell on which the position of the person sitting in the seat is fixed on the seat using easily adjustable and reliably fixable support elements.

[0007] This object is achieved according to the present invention by the fact that the support elements are situated above the two side edges of the seat and the distance between them in the transverse direction of the seat is adjustable.

[0008] The support elements that are adjustable and fixable in the direction transverse to the seat permit lateral support of the buttocks and thighs of the person sitting in the seat, which is optimally adjusted to the size of the person sitting in the seat. Thus, a single wheelchair may be manufactured, which is optimally adjustable to the width of the person sitting in the seat.

[0009] The accurate lateral support of the person sitting in the seat is required in particular in wheelchairs for patients suffering from spastic spasms. Such patients are subject to uncontrollable muscle contractions at irregular intervals which, as described previously, result in body extension. The narrow seat in the padded seat shell ensures that spasm-like movements are counteracted by soft contact elements and the person sitting in the seat does not hit a hard object with a body part. Of course, as in the wheelchairs known from the related art, all the contact surfaces of the backrest and the seat, as well as the support elements on the side facing the body of the person sitting in the seat are provided with padding.

[0010] The adjustable support elements according to the present invention ensure reliable lateral guidance, also known as adduction guidance or adduction truss pads. In particular, for spastically disabled children, the wheelchair according to the present invention is particularly advantageous, because it is adjustable to the increasing size during the child's growth.

[0011] The support elements are preferably pivotably attached to each longitudinal edge of the seat, which may result in a particularly simple adjustability. In particular, the pivotable attachment allows the support elements to be set obliquely to the vertical plane. Thus, the two opposite support elements may enclose trapezoidal spaces which enlarge downward. In this manner, the buttocks and the thighs of the person sitting in the seat are held by the support elements against being lifted from the seat.

[0012] At least one bracket carrying the support element is articulated on each longitudinal edge of the seat. Two brackets are preferably used for securing each support element.

[0013] In a particular embodiment of the seat shell according to the present invention, each longitudinal edge of the seat has a longitudinal bore hole in which a threaded rod is situated, which has a head on its front end for positive engagement of a wrench and which exerts a clamping force on the bracket when tightened. This mode of attachment allows the pivoting position of the bracket to be secured in a particularly simple manner. It is only necessary to loosen the threaded rod using the wrench, readjust the pivoting position, and retighten the threaded rod. The screw head of the threaded rod is preferably situated on the front side of the seat shell.

[0014] In a particularly preferred embodiment of the seat shell, each longitudinal bore hole is situated within an extruded profile on the lateral edge of the seat. Using known aluminum extruded profiles having a central longitudinal bore hole, which are manufactured in large quantities for windows or for the construction of transportable racks, for example, a reliable mount for the elements used for attaching the support elements to both sides of the seat shell may be provided.

[0015] The aluminum extruded profiles may be connected to a metal plate forming the seat in any desired manner. For example, a welded joint or a threaded joint is well suited for securing these profiles.

[0016] The threaded rod preferably exerts a tensioning force on two parallel brackets which jointly hold a support element. The two brackets are capable of securing the support element on the seat with sufficient stability to counteract the muscle forces produced by spastic extension spasms. In addition, the two brackets may be attached parallel to one another to a common connecting sleeve. The connecting sleeve may also be mounted in the longitudinal bore hole on the longitudinal edge of the seat, the threaded rod extending within the connecting sleeve. This provides a compact and easy to service fastening device for the support element.

[0017] In order to achieve the aforementioned oblique position of the support element with respect to the vertical plane which is settable within a certain range, the support element should be pivotably mounted on the bracket. The two opposite support elements may then be positioned either vertically and parallel to one another or at an angle to one another.

[0018] An advantageously simple and stable construction of the support element results if it has a metal sheet and a pad, a folded area of the metal sheet forming the receptacle for the pivot axis of the support element. The bracket should have a slit into which the folded area of the metal sheet is inserted, a draw spindle forming the pivot axis of the support element and generating a clamping force securing the brackets on the metal sheet passing through the bracket and the folded area of the metal sheet. This results in a fastening device similar to the one on the longitudinal edge of the seat on which the lower ends of the brackets are articulated. The screw head of the draw spindle should be situated on the front side of the seat shell and thus somewhat above the screw heads of the threaded rods. This makes it possible to initially set and fix the distance of a support element from the longitudinal center of the seat using the lower screw head of the threaded rod. Subsequently the inclination of the support element is settable using the upper head of the draw spindle.

[0019] If two brackets are used for attaching a support element, the draw spindles should pass through both brackets and folded areas of the metal sheet of the support element, simultaneously, which are clamped in slits by these brackets.

[0020] The present invention is elucidated in the following with reference to the attached drawing on the basis of exemplary embodiments, which show a seat shell having a plurality of adjustment possibilities.

[0021]FIG. 1 shows a side view of a seat shell according to the present invention on the chassis of a wheelchair;

[0022]FIG. 2 shows a side view of a part of an alternative connecting device connecting the backrest to the seat of the seat shell;

[0023]FIG. 3 shows a side view of the wheelchair of FIG. 1 with the backrest and seat in the pivoted position;

[0024]FIG. 4 shows a side view of a part of a wheelchair corresponding to the embodiment of FIG. 1, having an alternative connecting device;

[0025]FIG. 5 shows a sectioned view of an extruded profile and a connecting element along section line V-V of FIG. 1;

[0026]FIG. 6 shows a sectioned view of a double brace carrying the vertical frame of the chassis along section line VI-VI;

[0027]FIG. 7 shows a partially sectioned side view of the double brace of FIG. 6;

[0028]FIG. 8 shows a front view of pivoting lateral support pillows attached to the seat;

[0029]FIG. 9 shows an enlarged view of a bracket for the support pillows of FIG. 8;

[0030]FIG. 10 shows a side view of the support pillows of FIG. 8 with a sectioned fastening device;

[0031]FIG. 11 shows a sectioned view of the support surface along section line XI-XI of FIG. 10.

[0032] The seat shell illustrated in FIG. 1 generally comprises a backrest 1, a seat 2, and a footrest 3. Backrest 1 and seat 2 are shown in FIG. 1 without the textile protecting case in which they are usually encased. Prior to use by a patient, the contact surfaces for body parts are provided with padding and encased with the protecting case. This ensures a soft contact of the person sitting in the seat shell with the surface of the seat shell. The padding and case are mostly omitted in the figures for the sake of clarity.

[0033] Both backrest 1 and seat 2 have profiles 4 running on their two side edges. These are aluminum extruded profiles 4, whose cross section is visible in particular in FIG. 5. FIG. 8 shows that a longitudinally running profile 4 is attached to each side of seat 2. Backrest 1 also has a profile 4 on each of its sides.

[0034]FIGS. 5 and 9 show that profiles 4 have an essentially square cross section. A groove 5 is located on each side of profile 4. Each groove 5 has lateral undercuts 6, so that either screw heads or displaceable sliding blocks may be inserted in groove 5 with a positive fit. Profile 4 has a longitudinal bore hole 7 in its center.

[0035]FIG. 1 shows the preferred embodiment in which seat 2 and backrest 1 are pivotably linked to one another. A first base plate 12 is attached to the side of backrest 1 in longitudinal groove 5 on profile 4 using attachment screws 9. Screw head 10 (see FIG. 5) of attachment screw 9 is inserted in groove 5 with a positive fit. A cap nut 11 is threaded onto the thread of attachment screw 9. In the same way, second base plate 8 is attached to profile 4 on the side of seat 2.

[0036] Base plates 8 and 12 are pivotably connected using a pivot bolt 13. On the other side of the seat arrangement, not shown in FIG. 1, a similar connecting device is attached to profiles 4 of backrest 1 and seat 2 located there.

[0037] The bottom of seat 2 is held on chassis 15 of a wheelchair displaceably in the longitudinal direction of seat shell 2 by a displaceable carriage 14; the chassis 15 has a large rear wheel 47 and a steerable front wheel 48 on either side. In addition, seat 2 is pivotably linked to carriage 14. Furthermore, pivotable holding elements 16 are attached to the upper third of both side 10 profiles 4 of backrest 1; holding elements 16 link, pivotably about a pivot bolt 17, backrest 1 to frame 18 of chassis 15.

[0038] As FIG. 3 shows, in the event of an extending movement of a person seated in the seat shell, backrest 1 pivots backward with respect to seat 2 and moves about pivot bolt 17 of holding element 16. Because backrest 1 is attached to vertical frame 18 of chassis 15 by holding element 16, seat 2 must be pushed forward and pivot upward, which is made possible by carriage 14, to which seat 2 is pivotably articulated.

[0039] Pivot bolt 13, which permits backrest 1 to pivot with respect to seat 2, is located exactly at the height of the hip joint thanks to base plates 8, 12 which are preferably used. In the case of a growing person, the position of pivot bolt 13 may be readjusted continuously, because attachment screws 9, which hold base plates 8, 12, are located in elongate holes 19, 20 of base plates 8, 12, elongate holes 19, 20 extending transversely with respect to grooves 5 in profiles 4.

[0040] The same applies to footrest 3, which is supported by lateral base plates 21, which are attached to both sides of seat 2 in longitudinal groove 5. Lateral base plates 21 are connected to carrying elements 23 of footrest 3 via pivot bolt 22. Also in this case, the position of pivot bolt 22 may be adjusted by displacing attachment screws 9 along groove 5 on the one hand and by displacing elongate holes 24 through which attachment screws 9 pass on the other hand.

[0041]FIG. 4 shows an alternative embodiment of base plates 8′, 12′, and 21′, in which a plurality of individual bore holes are situated in bore hole rows 49 next to one another, instead of elongate holes. This embodiment also makes it possible to adjust the attachment of base plates 8′, 12′, and 21′ to profiles 4 transversely to their grooves 5. Lateral support pillows 50 on backrest 1, visible in FIGS. 1 and 4, are known as trunk pads, which support the upper body of the patient sitting in the wheelchair.

[0042]FIGS. 1 and 3 schematically show tension springs 25 and 26. Tension spring 25 draws carriage 14 backward, so that seat 2 is prestressed backward and backrest 1 is prestressed in the vertical, upright position. This prestressing force acts over the entire pivoting range between backrest 1 and seat 2, as well as over the entire displacement path of seat 2. Tension spring 26 draws footrest 3 into the angled position with respect to seat 2, also over the entire pivoting range of footrest 3.

[0043] Should the fastening device according to the present invention be designed to rigidly fastening a backrest 1 to a seat 2, a single rigid base plate 27 may be attached to grooves 5 of profiles 4 on each side of seat 2 via attachment screws 9 (see FIG. 2).

[0044] Fastening elements are also insertable into longitudinal bore holes 7 of profiles 4. For example, FIG. 1 shows that braces 28 for an adjustable holding device 29 for a head rest (not illustrated) is mounted on the upper section of longitudinal bore holes 7 of vertical profiles 4 on backrest 1. One brace 28 is mounted on either side of backrest 1 in the profile mounted there.

[0045] An additional fastening element for an adjustable lateral supporting element mounted in the longitudinal bore hole of profile 4 is described below in connection with FIGS. 8 through 11.

[0046]FIGS. 6 and 7 first show the adjustability seen in FIG. 1 of chassis 15 of the wheelchair. Vertical frame 18 is adjustable in size in the longitudinal direction of seat 2. For this reason, vertical frame 18 has, on its lower ends, two double braces 31 which are each insertable in a double tube 30 of chassis 15. Each brace of double brace 31 is hollow and, at its end, has a clamp body 32 resting on the oblique end of brace 31 via an oblique surface. Clamp bodies 32 may be drawn against the ends of double braces 31 using two draw spindles 33, so that clamping occurs within double tube 30, and vertical frame 18 is secured on chassis 15. As mentioned previously, such double tubes 30 in which a double brace 31 of vertical frame 18 is mounted are located on both sides of seat 2.

[0047]FIGS. 8 through 11 show a novel fastening device for adjustable lateral support elements 34. Each support element 34 has a folded metal sheet 35, to which a pad 36 is attached. Each support element 34 is attached to a profile 4 on one side of seat 2 using two brackets 37. As can be seen in FIG. 10 in particular, a connecting sleeve 38, obliquely parted in the center, on whose two parts the two brackets 37 are non-rotatably attached, extends in each profile 4 within longitudinal bore hole 7 with little clearance. A threaded rod 40, whose threaded front end is screwed into a clamp body 39, extends within connecting sleeve 38. The end of threaded rod 40 projecting outward carries a head screw 41, which is positively engageable with a wrench. The screw head is located on the front edge of seat 2 near footrest 3 (see FIG. 1). Clamp body 39 is displaced in the axial direction toward connecting sleeve 38 by twisting threaded rod 40. It is also displaced radially outward over the oblique surface of clamp body 39. Likewise, both connecting sleeves 38 are displaced radially with respect to one another over their oblique surfaces and are clamped within longitudinal bore hole 7 in profile 4 on seat 2. After tightening threaded rod 40, brackets 37 are fastened essentially rigidly to profile 4.

[0048] Support element 34 may be locked to the upper end of brackets 37 in a similar manner. As shown in FIG. 11, a draw spindle 42 is located within distance sleeves 43, 44. The front end of draw spindle 42 has a screw head 45. When draw spindle 42 is tightened, folded areas 46 of metal sheet 35 are clamped into slits 53 within brackets 37. Both screw head 45 of draw spindle 42 and screw head 41 of threaded rod 42 are located on the front end face of support element 34 and of profile 4 on seat 2. Each support element 34 may thus be adjusted as desired both in its inclination and its position in the transverse direction of seat 2.

[0049] As FIG. 8 shows, support elements 34 may be adjusted to different body widths in a broad adjustment range. Pads 36 of support elements 34 may also be set at an angle to one another, so that they enclose a trapezoidal space widening downward, for example. The support elements, which are also known as adduction guides, not only exert a lateral support force in this position, but also a holding force on the hip and legs of the patient sitting in the wheelchair that prevents the patient from slipping out upward.

[0050] Extruded profiles 4 are attached to backrest 1 and seat 2 in any suitable manner. They may be directly welded onto metal plates forming backrest 1 and seat 2, for example. A detachable joint, however, is also possible. FIG. 9 shows, for example, a threaded joint in which a connecting screw 51 is screwed into an internal thread of a sliding block 52, mounted in a longitudinal groove of profile 4, through the metal plate forming seat 2. Such threaded joints may be situated at different points along the length of profile 4.

List of Reference Symbols

[0051]1 backrest

[0052]2 seat

[0053]3 footrest

[0054]4 profile

[0055]5 groove

[0056]6 undercut

[0057]7 longitudinal bore hole

[0058]8 base plate

[0059]9 attachment screw

[0060]10 screw head

[0061]11 cap nut

[0062]12 base plate

[0063]13 pivot bolt

[0064]14 carriage

[0065]15 chassis

[0066]16 holding element

[0067]17 pivot bolt

[0068]18 vertical frame

[0069]19 elongate hole

[0070]20 elongate hole

[0071]21 base plate

[0072]22 pivot bolt

[0073]23 carrying element

[0074]24 elongate hole

[0075]25 tension spring

[0076]26 tension spring

[0077]27 rigid base plate

[0078]28 brace

[0079]29 holding device for head rest

[0080]30 double tube

[0081]31 double brace

[0082]32 clamp body

[0083]33 draw spindle

[0084]34 support element

[0085]35 metal sheet

[0086]36 pad

[0087]37 bracket

[0088]38 connecting sleeve

[0089]39 clamp body

[0090]40 threaded rod

[0091]41 screw head

[0092]42 draw spindle

[0093]43 distance sleeves

[0094]44 distance sleeves

[0095]45 screw head

[0096]46 folded area

[0097]47 rear wheel

[0098]48 front wheel

[0099]49 bore hole row

[0100]50 support pillow

[0101]51 connecting screw

[0102]52 sliding block

[0103]53 slit 

1. A seat shell, which is provided for attachment to the chassis (15) of a wheelchair or a stroller in particular, having a seat (2) and a backrest (1), as well as adjustable support elements (34) for supporting the person sitting in the seat shell, characterized in that the support elements (34) are situated above the two side edges of the seat (2) and the distance between them in the transverse direction of the seat (2) is adjustable.
 2. The seat shell as recited in claim 1, characterized in that a support element (34) is pivotably attached to each longitudinal edge of the seat (2).
 3. The seat shell as recited in claim 1 or 2, characterized in that at least one bracket (37) carrying the support element (34) is articulated on each longitudinal edge of the seat (2).
 4. The seat shell as recited in claim 3, characterized in that each longitudinal edge of the seat (2) has a longitudinal bore hole (7) in which a threaded rod (40) is situated, which has a head (41) on its front end for positive engagement of a wrench and which exerts a clamping force on the bracket (34) when tightened.
 5. The seat shell as recited in claim 4, characterized in that each longitudinal bore hole is situated within an extruded profile (4) on a lateral edge of the seat (2).
 6. The seat shell as recited in claim 4 or 5, characterized in that the threaded rod (40) exerts a tension force on two parallel brackets (34).
 7. The seat shell as recited in claim 6, characterized in that the two brackets (34) are attached parallel to one another to a common connecting sleeve (38).
 8. The seat shell as recited in claim 7, characterized in that the connecting sleeve (38) is mounted in the longitudinal bore hole (7) on the longitudinal edge of the seat surface (2).
 9. The seat shell as recited in claim 8, characterized in that the threaded rod (40) is situated within the connecting sleeve (38).
 10. The seat shell as recited in claims 3 through 9, characterized in that the support element (34) is pivotably mounted on the bracket (37).
 11. The seat shell as recited in claim 10, characterized in that the support element (34) has a metal sheet (35) and a pad (36), a folded area (46) of the metal sheet (36) forming the receptacle for the pivot axis of the support element (34).
 12. The seat shell as recited in claim 11, characterized in that the bracket (37) has a slit (53) into which the folded area of the metal sheet (46) is inserted.
 13. The seat shell as recited in claim 12, characterized in that a draw spindle (42) forming the pivot axis of the support element (34) and generating a clamping force securing the bracket (37) on the metal sheet (35) passes through the bracket (37) and the folded area (46) of the metal sheet (35).
 14. The seat shell as recited in claim 13, characterized in that the draw spindle (42) passes through two brackets (37) and folded areas (46) of the metal sheet (35) of the support element (34) simultaneously.
 15. The seat shell as recited in claim 13 or 14, characterized in that the draw spindle (42) has a screw head (45) on its front end for positive engagement of a wrench. 